In general, sapphire wafers are used to manufacture light-emitting diodes (LEDs) and the like. To transfer such an LED wafer, a picker to pick up the LED wafer may be used.
A conventional LED wafer picker creates predetermined vacuum by drawing air, and fixes an LED wafer. However, since such a vacuum adsorption scheme enables the LED wafer to come into direct contact with an adsorption pad, foreign substances attached to the adsorption pad may contaminate a surface of the LED wafer, or damage the LED wafer.
To solve the above problems, a non-contact type LED wafer picker may be used. The non-contact type LED wafer picker may not come into contact with the surface of the LED wafer, based on the Bernoulli's principle. A conventional non-contact type LED wafer picker may enable compressed air to quickly flow along a streamlined discharge surface, so that an LED wafer may be held in an adsorbed state at a predetermined distance from the discharge surface.
FIG. 1 is a diagram illustrating a cross section of a conventional LED wafer picker, FIG. 2 is a diagram illustrating a bottom of the conventional LED wafer picker, and FIG. 3 is a diagram illustrating an example of an operation of the conventional LED wafer picker.
In FIGS. 1 through 3, the conventional LED wafer picker may include a main body 110, and a guide member 120.
The main body 110 may have a structure in which air is drawn in from a top of the main body 110 and is discharged toward a bottom of the main body 110. In this instance, the air may flow out to both sides along a streamlined discharge surface 111 in the bottom of the main body 110.
The guide member 120 may be disposed below the discharge surface 111, and may guide the air so that the air may flow along the discharge surface 111. The guide member 120 may include a plurality of fine holes 121 through which air flows.
Specifically, since highly compressed air drawn in from the top of the main body 110 may quickly flow along the streamlined discharge surface 111, a central portion of the discharge surface 111 may be temporally maintained in a vacuum state. Accordingly, negative pressure may be generated in an upward direction from the bottom of the main body 110, so that an LED wafer 199 (FIG. 3) disposed below the main body 110 may be held in an adsorbed state through the fine holes 121 of the guide member 120.
However, in the conventional LED wafer picker, a suction force required to adsorb the LED wafer 199 is reduced due to the fine holes 121 of the guide member 120.
Additionally, when the LED wafer 199 is held in the adsorbed state, there is concern that a top surface of the LED wafer 199 may come into contact with the guide member 120. When the top surface of the LED wafer 199 comes into contact with the guide member 120, various foreign substances may be attached to the top surface of the LED wafer 199 and, accordingly, defects may occur.